Black water

THE BLOOM

First noticed in mid-December of last year, and photographed by NASA’s SeaWiFS satellite, the Black Water that can be found off of the coast of Florida is likely to be nothing more than a giant Algae bloom. The bloom, peaking around February 4, 2002, once covered an estimated 700 square miles north of the Florida Keys and west of mainland Florida. The Algae making the bloom is believed to be a non-toxic relative of red tide. Gil McRae, of the Marine Research Institute, said, "Nothing indicates that this is anything other than a natural event." The cause is likely to be diatoms, and the discoloration due to extra plant mass in the water, which could cause trouble when it settles to the bottom of the ocean. The cause of this bloom remains unknown; some suggested that it might be a natural occurrence, like a hundred-year flood. Pictures of the bloom can be found at the addresses at the bottom of this write up.

EFFECTS OF THE BLOOM

While no one can really be sure of what caused the massive bloom, the effects of it can be seen already. While the bloom isn’t a killer, like red tide, fishermen have noticed less fish than they normally find. Catches of Spanish Mackerel and kingfish are reported to be scant. Richard H. Pierce, a marine chemist and toxicologist with Mote Marine Laboratory, provides an answer: "One of the characteristics of a heavy algae bloom is that at night, plants don't produce oxygen but use it up, take the oxygen out of the water at night, so fish would avoid that area. Because they of course would die… A bloom of microscopic algae absorbs sunlight and would make the water look black." Divers have found some small fish dead at the ocean’s floor. Ken Nedimyer, who has been diving in the Keys since the 1970s, noticed several things during a dive he made on March 22, 2002: "Half or more of some sponge species — animals that filter quarts of water per hour as they feed — were dead after the black water moved through… I also saw dead vase sponges, 'stinker' sponges, red and yellow ball sponges, and red tree sponges." The bloom also killed some Brain Coral. Other coral were not harmed but had a white crust on them: "I've seen these corals under every imaginable circumstance, from 55 degree water to 90 degree water, from calm, clear sea conditions to rough cloudy conditions, and I've never seen them look quite like this."